Oscillators are building blocks in modern wireless and wireline communications systems. One important factor in designing oscillators is frequency stability, which is usually quantified as phase noise. Phase noise performance is particularly important in oscillators. The phase noise performance of oscillators is a factor in the overall system performance of many communication systems, such as in its effect on interference in adjacent wireless communications channels. Control of phase noise is also of importance in oscillators that are implemented as integrated circuits, such as part of integrated transceivers. The efforts to improve phase noise performance for integrated oscillators have focused on increasing the quality factor, “Q,” of the resonator, among other things.
Oscillators are also used to generate in-phase and quadrature-phase output signals. These in-phase and quadrature-phase signals are used for many modern radio architectures. Conventional systems and processes for implementing local oscillators that are used to generate in-phase and quadrature-phase signals include poly-phase filters, coupled oscillators, or digital dividers. Such approaches can result in large power consumption and phase noise degradation.